"When you grow up, you want to be a pro and be No. 1 in the world and you don't realize actually how hard it is," said the 24-year-old Chicago native who defeated No. 24 seed Andreas Seppi 6-4, 2-6, 6-3, 4-6, 7-5 to reach the third round at the Australian Open. "But it's a dream everybody has and then when you get out there, you realize how tough it is and you kind of decide or debate if you want to do it or not.

"I've definitely had those moments. It wasn't all up. There were some downs, a lot of downs. But at the end of the day, this is what I want to do. I love tennis, I love competing. I don't want to do anything else unless I was forced to. I'm happy to be here."

That much happier that he is back on the pro tour after spending a week playing on the Challenger circuit after a 2012 when he went 17 matches without a victory.

"It's not where you want to be but you have to do what you have to do to get back to where you want to be," said Young, whose career-high world ranking was 38th. "In 2012, I think I won five tour matches or matches period, and that's not going to keep you on the main tour. So I had to go back down, win some matches, get some confidence and I happen to be back playing well and I hope I can keep improving every week and stay at this level. This is where I want to be and where everybody wants to be."

Young is one of six Americans -- and two American men along with Sam Querrey -- who remains in the draw. Jack Sock was eliminated Thursday by No. 25 seed Gael Monfils 6-7 (2), 5-7, 2-6.

"This was 9,000 percent better for me this year than last year at this time," Sock said. "Last year, I destroyed my ankle in the qualies here. I feel good about my game, I've improved in a lot of areas, I feel good physically and mentally. I'm looking forward to the rest of the year. I'm going to take away a lot of positives from this."

As for Young, he defeated Seppi, who eliminated Australian favorite Lleyton Hewitt in the first round in an epic five-setter. Young will next meet former junior foe and No. 16 seed Kei Nishikori in the third round.

The Young-Seppi match was suspended with all others on the outside court, under the extreme heat policy, after Young dropped the fourth set.

"It was actually good," Young said. "It was getting really hot and really tough for both of us. I was losing some of my bearings. … It's not good, not something I want to experience again, but next time I'll be better prepared to deal with it."

Young said he was not so far removed from the tour that he could not envision winning a second-round match.